Compound valve



Feb. 18, 1941. MORlN HAL 2,232,467

' COMPOUND VALVE Filed Sept. 5, 1940 INVENTOR GZQRGEQMORINMA I'M/LEJ-Qmurofl Patented. Feb. 18, 1941 COMPOUND VALVE George G. Morin andEmile J. iUarleton,

Holyoke, Mass.

Application September @1940, Serial No. 355.432

6 Claims.

This invention relates to hydraulic control valves of the general typeshown in our Patent 2,121,389, June 21, 1938. The valve described inthat patent received fluid under pressure from a constant pressuresource and delivered it' at a pressure'which could be regulatedaccurately to any degree desired under both static and movingconditions. The regulation of pressure in that valve depended upon thecomprehsion of a spring 1 which maintained the fluid pressure at alltimes when the source was out off by the regulating valve, In manyinstances it has proved desirable to use a higher pressure than caneconomically be controlled by a. compression spring mounted as describedin that prior patent since the heavier types of springs are hardertomake and more difllcult to maintain inaccurate condition. I

It is the object of the present invention to provide a valve by which a,relatively high unit hydraulic pressure at the delivery end of the valvemay be controlled by a compression spring of moderate size. A furtherobject is to produce a valve of this character of simple constructionand in which those valve parts which have to be made in concentricrelation can be kept large enough to permit accurate and readymachining. Additional objects will appear from the following descriptionand claims. l 3 Referring to the drawing:

Figs. 1, 2, and 3 are longitudinal sections through a. valveconstruction in accordance with the invention-Fig. 1 showing the valvein discharging position; Fig. 2 in a. position feeding pressure fluidfrom the inlet line directly to the exhaust; and Fig. 3 showing thevalve in balanced or static position.

The valve is composed of two sections, a low pressuresection which isconstructed substan- 49 tlally in accordance with our prior patent, and

a highpressure section connected to and operated by it. The low pressuresection is contained wl-thina cylinder Ill within which runs a piston llhaving an annular groove or channel i2 around its central part which inall operative positions overlies an inlet port It. The piston i-l mayhave suitable rings to preserve fluid tightness which are not necessaryto illustrate in the drawing. Within the piston His a bore M in 2whiclra pilot valve I5 may slide. The pilot valve has a centralcircumferential channel 16 which maybe shifted into alignment with aninlet port I! extending trom the bore i4 into the channel l2; and whichmay also come into registration with a delivery port I! o'pening'at llat theend of the piston l l. The pilot valve I5 is fitted with a controlhandle 20 extending outwardly through a stuffing box 2| at the end ofthe casing and has a hole 22 through its centerso that the pressurespressure into aohamber 23, located at the left hand end of the pistonand which may beconsidered at the present stage of the description asbeing blocked off in any suitable way so that 15 a pressure may be builtup. This will cause the piston I I to move toward the right against theresistance of a compression spring 24 mounted between the piston and theend of the casing. When 7 the piston hasmoved into the position of Fig.3, 2 in which the exhaust port l8v is blocked off bythe end 25 of thepilot valve, the total pressure in the chamber 23 will balance the forceexerted by thecompressed spring 24. The valve will remain in thiscondition, with the unit pressure in the g5 chamber 23 fixed at the.point determined by the setting of the rod 20, unless some outsideconditions disturb this equilibrium. In order to prevent the piston Hbeing moved so far to the right that the spring 24 will be compressedbeyond a 3 safe limit, a stop 50 is preferably secured to the rod 20 tolimit its movement.

. The arrangement as described above is substantially that covered byour prior patent referredto with the exception that in that prior 35patent the chamber 23 was directly connected to the delivery line inwhich the'iluid pressure was to be controlled. In the present case it isdesirable to achieve a higher unit pressure than can be given in thechamber 23 by the mecha- 0 nism already described. For this purpose asecond piston valve 26 is located within a bore 2 1 of a casing 28mounted in fixed relation to the casing III as by tie bolts 29. Thepiston valve 2-6 p is made of a cross-sectional area substantially lessthan that of the low pressure piston valve 1 I and at its end bearsagainst an intermediate piston 30 sliding in a .bore 3! which may be acontinua-' tlon of the bore" within the casing ill ii desired.

This piston 30 is subjected on one side to a hy- 50 m draulic'pressurewithin the chamber 23 and at its otherslde to the mechanical-pressure ofthe pisfton valve 26. At the end where it contacts with.

the intermediate piston the high pressure piston valve is solid, but itsother end is hollow asshown 68 at 3| in Fig. l, and the two pistons 26and 30 form in effect a single differential piston although madeseparate for purposes of convenience in manufacture. Between the twosections 26 and 3| there is a ported or slotted portion 32 which may beshifted into registration with an annular inlet port 33, an annularexhaust port 34, or an intermediate unported section of the bore 21. Theport 33 is connected to an inlet port 36 which may receive fluidpressure from the same source as the port i3 or from a higher pressuresource, if desired; and the port 34' is connected to a discharge line 31which may join the discharge line 38 into which the chamber 23 is ventedwhen the low pressure valve is in the condition of Fig.

1.- By shifting valve 26 successively to the positions of Figs. 1 and 2,a port 4| towhioh the devices to be operated are connected may be placedin communication with ports 31 and 36 for exhausting or delivering fluidto the devices respectively. If the valve 26 is placed in the midposition of Fig. 3, whatever pressure is already existing in' thedevices connected to port 4| is maintained. In order to prevent liquidbeing trapped v within the chamber 36 at the left hand end of theintermediate piston 30 this chamber is preferably connected as bypassages 40 to the exhaust port 34.

i It will be seen that any pressure built up in the dischargeport 4|will act against the solid part of the piston 26. This piston is ofrelatively small area so that the total pressure will not be large. Thepiston acts mechanically against tion of piston 26 and intermediatepiston 30 causes piston 26 under working conditions, to act like adiflerential piston having working faces of 4I may-by this directly'inthe chamber 23.

largeand small areas corresponding respectively to the area of piston 30and the area of piston 26. The total pressure against the piston 26 isof course ultimately balanced by the compressive force of the spring 24,but the unit pressure in pounds per square inch in the discharge lineconstruction be made substantially greater than that which can beproduced Since the latter chamber represented the connection to theexhaust line in our prior patent there is a very substantial increase inthe unit pressure available by this means.

We claim:

1. A controller for fluid pressure devices comprising a casing having aport for connection to the devices, a main inlet port and a main outletport, a supplementary inlet port and a supplemental-y outlet port foradmitting and exhausting fluid, a difl'erential piston valve havingworking faces of large and small area respectively and slidable back andforth in the casing for connecting the main inlet and outlet portsselective- 1y with the port for the devices and bodily movable in onedirection by and having its working face of smaller area exposed to thepressure supplied to the devices, a pilot piston slidable in the casingadjacent the diiferential piston and having a channel for connecting thesupplementary inlet and outlet ports to deliver fluid to and exhaustfluid from the working face of larger area on the differential-pistonfor moving vsaid differential piston in a direction opposite to that inwhich it is moved by the fluid supplied to the devices. said pilotpiston being movable in one direction by and exposed on one side ,-tofluid supplied to said working face of larger area, yieldable meansacting on the other side of said pilot piston for moving it in theopposite direction, a valve element movable back and forth within saidpilot piston to alternately connect the supplementary inlet and outletports selectively with the channel in said pilot piston and a controlrod connected to said valve element and extending through the casing formoving said valve back and forth.

2. A controller for fluid pressure devices comprising a casing havingmain inlet and outlet ports, supplementary inlet and outlet ports and aport for connection to the devices, a main piston valve slidable backand forth to connect the main inlet and outlet ports with the port forthe de-- vices, and connected to be moved in one direction by fluidsupplied to said last named port, and a pilot piston valve slidable backand forth to connect the supplementary inlet and outlet ports to movethemain piston valve in the opposite direction, said pilot piston valvebeing moved in one direction by and havin one face exposed to fluidadmitted to move the main piston in said opposite direction and beingmoved in the opposite direction by yielding pressureexerted on thesecond face.

3. A controller for fluid pressure devices comprising a casing havingmain inlet and outlet ports, supplementary inlet and outlet ports, and aport for connection to the devices, a main ,siston valve slidable backand forth to connect the main inlet and outlet ports with the port forthe de-: vices, and connected to be moved in one direction by fluidsupplied to said last named port, a pilot piston valve and asupplementary piston valve both mounted in the casing, said last twovalves being relatively slidable back and forth to connect thesupplementary inlet and outlet ports to move the main piston valve inthe opposite directionfrom that in which it is moved by fluid suppliedto the port for the devices.

4. A controller for fluid pressure devices comprising a casing havingmain inlet and outlet ports, supplementary inlet and outlet ports and aport for connection to the devices, a main piston valve havingoppositely disposed working faces and slidable back and forth to connectthe main inlet and outlet ports with the port for the devices and havinga channel to direct fluid supplied to the port for the devices againstone working face to thereby rection, a pilotpiston valve andasupplementary piston valve both mounted in thelcasing, said last twovalves being relatively slidable back and forth to connect thesupplementary inlet and outlet ports to supply fluid to the secondworking face of the main piston valve to thereby move the main pistonvalve in the opposite direction.

5. A controller for fluidpressure devices comprising a casing havingmain inlet and outlet ports. supplementary inlet and outlet ports and amove the main piston in one diarea to thereby move the main piston inone di rection, a second channel in communication with other iace ofsaid pilot piston the working face of large area. a pilot piston valveand a supplementary valve slidable relative to each other to connect thesupplementary inlet and outlet ports with said second channel to therebymove the main piston in the opposite direction, said pilot piston valvehaving oppositely disposed working laces, one of which is incommunlcation with the second channel whereby said pilot piston is movedin one direction by fluid in said channel, a yielding member acting on.the to move the pilot piston in the opposite direction, and a controlrod connected to said supplementary valve and extending through thecasing for moving said supplementary valve back and iorth.

6. A controller for fluid pressure devices comprising a body portion andtwo end portions. a

substantially constant diameter cylindrical bore in the body portion, aconstricted cylindrical bore in one end portion, an inlet port, anoutlet port, and a port tor the devices iormedin said last named endportion, and in communication with said constricted bore, asupplementary inlet port formed in said body portion and a supplementaryoutlet ort i'ormed in said other end portion, both said last ports beingin communication with the bore in the body portion, a main piston valveslidable back and forth in said constricted bore to connect the maininlet and outlet ports to the port for thedevices, said main valvehaving two oppositely disposed working faces. one of large and one oismall area, both iac'es lying in the bore oi the body portion, and achannel in the main piston valve connecting the port tor the deviceswith the worming iace or smaller area, a pilot piston sliolable back andforth in the bore of the main body having two oppositely disposed iacesthe first of which is in communication with the working face oi'largearea on the main pis ton, a channel in the pilot piston communicatingwith said first race, a supplementary valve able back and iorth withinthe pilot piston to connect the supplementary inlet and outlet portswith the channel in the pilot piston, a yieidable member acting againstthe second face 01 the pilot piston, and a control rod connected to thesupplementary valve and extending coaxially with said bore in the bodyout through the end portion remote from the main piston valve (or movingsaid supplementary valve.

GEORGE G. MORAN. EMILE J. CARLETON;

Slick.

